1. [Field of the Invention]
The present invention is related to a driving circuit, more particularly, to a circuit for driving a display panel using a driving capacitor,
2. [Description of the Prior Art]
As the technology advances, more and more new kinds of electronic products satisfying our different needs become commercially available. Since the conventional cathode ray tube displays have drawbacks in large volume, high power consumption and radiations harmful to frequent users, they are gradually replaced by liquid crystal displays. The LCD is superiors in small volume, low power consumption and radiation, and now becomes the most popular display used in electronic products.
Further, with the fast development of manufacture technology of display panels, the cost of touch panels is significantly reduced so that the touch panels are generally used in different kinds of consumer product, such as mobile phones, digital cameras, MP3 players, PDAs and GPS. In these kinds of products, touch panels are mainly used for a friendly user interface which improves the interaction between users and the machine, and the convenience of user's input operations.
In order to meet the supply voltage requirement of a wider and higher range, such as 2.3V˜4.6V, only by using a single voltage source, and also to reduce the circuit area of the driver IC in the display, different driving schemes are provided. Examples are the application of operational amplifiers and voltage dividers. However, in those driving schemes, specific power IC and DC-DC converters become necessary, which complicates the circuitry of the driver IC and results in more externally connected components. Especially in the case of processing images of large bit number or by using all three Gamma curves (RGB), due to a large number of gray scales used, the circuit area of the digital-to-analog converter will greatly increase, which results in increase of cost of the driver IC.
Therefore, it is necessary to provide a new driving scheme whereby the circuit area needed for a source driver processing images of large bit number can be reduced, and the power system of the display having a large dynamic range of voltage can be also simplified.